Oil pan and drain plug assembly



July 16, 1963 R. M. BUCHWALD OIL PAN AND DRAIN PLUG ASSEMBLY Filed May1, 1961 I NV EN TOR. Mammy? ram/Er United States Patent 3,097,663 OILPAN AND DRAIN PLUG ASSEMBLY Robert M. Buchwald, Berkley, Mich., assignorto General Motors Corporation, Detroit, Mich., a corporation of DelawareFiled May 1, 1961, Ser. No. 106,700 4 Claims. (Cl. 137-351) Thisinvention relates to an internal combustionengine and more particularlyto an oil pan and drain plug assembly for an engine adapted for use in amotor vehicle.

The oil pan of an automative type internal combustion engine isgenerally of a relatively thin wall construction depending from thecrankcase defining side walls of the engine block. The sump of such athin wall oil pan usually has a drain opening defined by a threadedprotrusion adapted to receive a suitable pipe-threaded drain plug. Sucha protrusion necessarily decreases the engine and vehicle road clearanceor requires a corresponding increase in the mounting height of theengine relative to the vehicle frame and road level. Such drain plugprotrusions are vulnerable to terrain obstacles which may tear orfracture the oil pan or otherwise result in failures of the oil pan anddrain plug seals. Such conventional drain plug arrangements are alsosusceptible to improper tightening with resultant oil loss due to threadleakage and loosening and loss of the drain plug.

The instant invention contemplates an improved oil pan and drain plugarrangement which eliminates the normal oil pan drain plug protrusion,provides adequate sealing with minimal plug tightening effort, andprevents loosen ing and loss of the plug under engine operatingconditions.

The foregoing and other objects, advantages and features of theinvention will be apparent from the following description of a preferredillustrative embodiment thereof having reference to the accompanyingdrawing, in which:

FIGURE 1 is a side elevational view of the lower crankcase portion of aninternal combustion engine with a portion of the oil pan broken away andin section to show the illustrative environment of the invention;

FIGURE 2 is an enlarged sectional view corresponding to the broken awayportion of FIGURE 1 and is taken substantially in the direction of thearrows and in the plane of the line indicated at 22 of FIGURE 3; and

FIGURE 3 is a fragmentary elevational view taken substantially in thedirection of the arrows 3-3 of FIG- URE 2.

Referring more particularly to FIGURE 1, the crankcase defining portionof an internal combustion engine for a motor vehicle is partially shownand indicated generally by the reference numeral 10. The engine includesa cylinder block 12 having side and end walls 14 defining the upperportion of the crankcase chamber and terminating in a peripheral flangedpan rail 16. The pan rail 16 sealingly engages the mounting flange 18 ofan oil pan 20 which is sealingly secured to the pan rail flange by aplurality of bolts 22. The oil pan is of a drawn or cast thin walledconstruction and defines the lower portion of the crankcase chamber. Anoil sump 24 is formed adjacent one end of the oil pan and has a drainport 26 opening through the bottom wall 28 thereof.

As best seen in FIGURE 2, the port 26 is flared downwardly on a slightradius and is scalable by a drain plug assembly 30. This drain plugassembly is constructed in accordance with the invention and suitablysupported by the sump defining bottom wall 28. The drain plug as sembly30 includes a perforated support member 32 of stamped configurationhaving arcuate peripheral flange segments 34. These flange segments aresuitably secured to the bottom wall 28 of the sump in concentricrelation to the drain port 26. The several flange segments are inter-3,097,663 Patented July 16, 1963 sected and separated by curved legs 36of channeled cross-section which extend radially inwardly and upwardlyto an internally threaded cylindrical support portion 38. Thiscylindrical support portion is spaced concentrically of the drain port26. The several legs cooperate with the peripheral flange portions 34and the bottom sump wall 28 to define a plurality of open drain ports 40and 42, respectively.

The upper cylindrical portion 38 of the perforated support memberthreadably mounts the upper shank portion 48 of a valve or drain plugmember 50. The lower end of the plug 50 is provided with a port closinghead or flange 52 having an annular undercut groove 54 opening towardthe port 26. This groove mounts and retains a replaceable resilientO-ring seal 56 of suitable oil resistant material, such as neoprene.This seal is sealingly engageable with the tapered curved seat providedby the drain opening 26. The lower flanged end of the drain plug isprovided with a wrench socket 58 centrally inwardly of its O-ringmounting groove. Thus the drain plug may be opened and sealingly closedby threadable rotation relative to the support member 32 by use of asuitable wrench.

In addition to its scaling function, the O-ring 36 coacts with thehydraulic pressure applied to resiliently lock the plug 50 againstrotation in a port opening direction under engine operating conditions.As indicated above, the instant drain plug assembly has furtheradvantage in that the plug 50 cannot be removed and misplaced or lostdue to improper tightening.

While the foregoing description has been limited to one illustrativeembodiment of the invention, it will be readily apparent that variousmodifications might be made therefrom without departing from the spiritand scope of the invention as defined in the following claims.

I claim:

1. In combination with a thin wall engine oil pan defining an oil sumpchamber and having a drain aperture in the bottom wall thereof, a drainclosure assembly comprising a support member mounted within said oilsump chamber, and having a peripheral flange portion defining aplurality of arcuately spaced flange segments secured to said bottomwall in radially spaced concentric relation to the drain aperture, aplurality of port defining legs bent upwardly and radially inwardly fromsaid peripheral flange portion and supporting an internally threadedcylindrical portion in coaxial spaced relation to the drain aperture,said legs cooperating with said cylindrical and peripheral flangeportions to define a plurality of primary oil drain ports and said legsbeing upwardly and transversely bowed and cooperating with said bottomwall between said flange segments to define a plurality of secondary oildrain ports, and a drain plug member having a shank portion threadablymounted within said cylindrical support portion and a head portionhaving an annuler groove therein opening toward said bottom walladjacent said aperture, a resilient seal mounted within said groove andsealingly and frictionally engageable with the bottom wall adjacent saidaperture to restrain opening rotation of said drain plug member, andsaid head portion further sealingly engaging said bottom wall outwardlyof said groove and aperture and limiting resilient deflection of saidresilient seal.

2. In the combination set forth in claim 1, the head portion of saiddrain plug having outwardly accessible means adapted to receive a wrenchelement for threadably opening and closing rotation of said plugrelative to said drain aperture.

3. In combination with a thin wall receptacle having a drain aperture inthe bottom wall thereof, a drain closure comprising a support membermounted within said receptacle and having a peripheral flange portiondefining a plurality of arcuate flange segments secured to said bottomwall in radially spaced concentric relation to the drain aperture, and aplurality of port defining legs extending upwardly and radially inwardlyfrom said per ripheral flange portion and supporting an internallythreaded cylindrical portion in coaxial spaced relation to the drainaperture, said legs and said cylindrical and flange portions cooperatingto define primary oil drain ports therebetween and said legs beingtransversely bowed upwardly and cooperating with said bottom wallbetween said flange segments to define a plurality of secondary oildrain ports, and a drain plug member having a shank portion threadablymounted within said cylindrical support portion and a head portionsealingly and frictionally engageable with said bottom wall adjacentsaid aperture to restrain opening rotation of said drain plug member.

4. In the combination set forth in claim 3, the head portion of saiddrain plug having an annular groove there- References Cited in the fileof this patent UNITED STATES PATENTS 462,478 Errington Nov. 3, 18911,621,155 Davenport Mar. 15, 1927 2,350,748 Gabel June 6, 1944 2,685,296Boosman Aug. 3, 1954 2,877,867 Cain et a1. Mar. 17, 1959 2,894,718Englert July 14, 1959 2,959,392 Von Platen et al. Nov. 8, 1960

3. IN COMBIANTION WITH A THIN WALL RECEPTACLE HAVING A DRAIN APERTURE INTHE BOTTOM WALL THEREOF, A DRAIN CLOSURE COMPRISING A SUPPORT MEMBERMOUNTED WITHIN SAID RECEPTACLE AND HAVING A PERIPHERAL FLANGE PORTIONDEFINING A PLURALITY OF ARCUATE FLANGE SEGMENTS SECURED TO SAID BOTTOMWALL IN RADIALLY SPACED CONCENTRIC RELATION TO THE DRAIN APERTURE, AND APLURALITY OF PORT DEFINING LEGS EXTENDING UPWARDLY AND RADIALLY INWARDLYFROM SAID PERIPHERAL FLANGE PORTION AND SUPPORTING AN INTERNALLYTHREADED CYLINDRICAL PORTION IN COAXIAL SPACED RELATION TO THE DRAINAPERTURE, SAID LEGS AND SAID CYLINDRICAL AND FLANGE PORTIONS COOPERATINGTO DEFINE PRIMARY OIL DRAIN PORTS THEREBETWEEN AND SAID LEGS BEINGTRANSVERSELY BOWED UPWARDLY AND COOPERATING WITH SAID BOTTOM WALLBETWEEN SAID FLANGE SEGMENTS TO DEFINE A PLURALITY OF SECONDARY OILDRAIN PORTS, AND A DRAIN PLUG MEMBER HAVING A SHANK PORTION THREADABLYMOUNTED WITHIN SAID CYLINDRICAL SUPPORT PORTION AND A HEAD PORTIONSEALINGLY AND FRICTIONALLY ENGAGEABLE WITH SAID BOTTOM WALL ADJACENTSAID APERTURE TO RESTRAIN OPENING ROTATION OF SAID DRAIN PLUG MEMBER.